Why Is the WBS Important?

The Project Management Institute (PMI) considers the WBS the most important tool of the project manager. Why?

More than any other project management tool, the WBS provides the foundation for defining and organizing the work needed to fulfill the project objectives. Through the WBS, the work to produce the targeted deliverables is structured, assigned, scheduled, tracked, and reported. Through the WBS, the work of the project is effectively represented and communicated to all stakeholders. A well-done WBS accomplishes the following objectives for the project manager:

• Manage the Pieces It provides a mechanism to manage any project size or complexity. Through decomposition, you can manage the pieces (work packages) rather than the whole project.

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  Any work not defined in the WBS is considered to be outside the project scope.

• Better Work Definition, Less Changes It enables identification of all necessary work for the project and only the necessary work. It also reduces the number of items that "slip through the cracks" as well as the "Oh, I didn't think of that!" moments.
• Better Estimates, Better Planning It improves the accuracy of cost, duration, and resource estimates.
• Better Control It defines a baseline for performance measurement and control.
• Clear responsibilities It facilitates clear responsibility assignments at both an individual and organizational level.
• Stakeholder buy-in on scope work effort It facilitates understanding and buy-in of the project scope, the project approach, the work effort involved, and alignment between scope and work from each stakeholder.

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  A well-done WBS can become a template for similar, future projects.

• Tighter management integration It provides a mechanism to relate the work directly to schedule, budget, and resource allocation plans.
• Better team performance It allows each team member to easily understand how his or her work fits into the overall project, how it impacts the work of other team members, and to stay focused on deliverables.
• Risk factors are identified early Through decomposition of the work, a more complete and effective risk analysis can be performed during project planning.
• Confidence increases When people see that the work of the project is structured, definable, and doable, their confidence level in the project increases.